On Welfare Losses Due to Imperfect Competition
研究了企业追求规模（如销售收入或市场份额）对市场绩效的影响，发现均衡福利损失随企业数量增加而迅速减小，在多数实际市场结构中低于5%，且仅需市场份额信息即可估算。
Corporate managers and executive compensation in many industries place significant emphasis on measures of firm size, such as sales revenue or market share. Such objectives have an important—yet thus far unquantified—impact on market performance. With n symmetric firms, equilibrium welfare losses are of order 1/ n 4 , and thus vanish extremely quickly. Welfare losses are less than 5% for many empirically relevant market structures, despite significant firm asymmetry and industry concentration. They can be estimated using only basic information on market shares. These results also apply to oligopsonistic competition (e.g., for retail bank deposits) and strategic forward trading (e.g., in restructured electricity markets).